SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ec95ec9ff98ceebcea0cc62374d41da59d85e52483ecd73b78406657995679d' 
  AND token = 'Cz3WVHgb3BVgqtLmdOu9puTZbpJjKssIf8Hi0pxg9Yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}